Preparation of N, P co-doped activated carbons derived from honeycomb as an electrode material for supercapacitors

In this study, we use N, P co-doped activated carbon prepared from honeycomb as an electrode material for supercapacitors. The texture characteristics of the materials are determined by using nitrogen adsorption analysis. Thermal properties, the crystal structure/phase composition and surface element composition are observed by TGA, XRD and XPS, respectively. The morphologies of the samples have been characterized via FESEM and HRTEM. In order to further study the surface functional groups and degree of graphitization (conductivity) of the samples, we have conducted FTIR and Raman spectra tests. The electrochemical performance is investigated using an electrochemical workstation. In 3 M KOH electrolyte solution, N, P co-doped activated carbon shows an excellent electrochemical performance with good high specific capacitance (375.0 F g(-1) at 0.5 A g(-1)) and remarkable rate capability (315.1 F g(-1) at even 10 A g(-1)). It also shows excellent cycle performance, after 10 000 charge and discharge cycles the specific capacitance was still maintained as the original 98.7%. In addition, we fabricate a symmetric supercapacitor device to further to study the electrochemical performance of N, P co-doped activated carbons. At a current density of 1.0 A g(-1), the symmetric supercapacitor exhibits an excellent cycle performance in that the specific capacitance was maintained as the original 98.1% after 10 000 charge-discharge cycles. The symmetric supercapacitor gives a maximum energy density of 27.6 W h kg(-1) at a power density of 398.4 W kg(-1).